Absorbent articles having antimicrobial properties and methods of manufacturing the same

ABSTRACT

According to one embodiment, an absorbent article includes a moisture-impervious outer layer, an inner layer substantially co-extensive with the outer layer, and an absorbent layer interposed between the outer layer and the inner layer. The inner layer is treated with at one least substance including dimethicone and/or at least one antimicrobial booster. The absorbent layer is treated with at least one antimicrobial agent.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/463,313 filed on May 8, 2009, allowed as U.S. Pat. No. 9,717,818,which is incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to an absorbent article and, inparticular, to an absorbent article having antimicrobial properties.

BACKGROUND

Millions of Americans of all ages suffer from incontinence of the bowelor bladder. Whether an infant, adult, or elderly person, the underlyingcause of incontinence varies but the method of treatment typicallyinvolves absorbent article products. Adult incontinent briefs,disposable diapers and underpads can alleviate some of the emotional andphysical discomfort of incontinence by absorbing and containing liquidand other discharges from the human body to prevent body and clothingsoiling.

However, the moisture-impervious layer that typically prevents absorbentarticles from leaking also prevents air circulation, thus creating awarm, moist environment where bacteria and fungi can thrive. When fluidsand discharge are introduced to the diaper, various bacteria from thewearer's digestive system are also present. Most bacteria are harmlessor even beneficial to the wearer while in the digestive system; however,after urination or defecation, some bacteria (e.g., StaphylococcusAureus and Streptococcus) are dangerous microbial pathogens that cancause infectious diseases. Yet even benign bacteria can cause unpleasantodors or lead to urinary tract, bladder, or kidney infections. Moreover,prolonged exposure to urine and/or feces allows yeast-like fungi (e.g.,Candida Albicans) to develop and cause uncomfortable diaper rashes.

Accordingly, a need exists for absorbent articles that can prevent orinhibit the growth of microbes in or on absorbent articles.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other advantages of the invention will become apparentupon reading the following detailed description and upon reference tothe drawings.

FIG. 1 illustrates a top view of an outer layer of a disposable diaperaccording to one embodiment.

FIG. 2 illustrates a cross-section view generally taken through sectionline 2-2 of the diaper of FIG. 1.

FIG. 3 illustrates an operational flow diagram for manufacturing adisposable diaper according to one embodiment.

While the invention is susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and will be described in detail herein. Itshould be understood, however, that the invention is not intended to belimited to the particular forms disclosed. Rather, the invention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Absorbent articles as described herein generally include amoisture-pervious inner layer, an absorbent layer, and amoisture-impervious outer layer. Although the remainder of thedescription will be specifically directed to a disposable diaper, it isto be understood that the embodiments may also be implemented on otherabsorbent articles such as, for example, adult incontinence briefs andunderpads and that the properties and uses described below apply tothese other absorbent articles as well.

Referring to FIG. 1, a top view of a disposable diaper 10 according toone embodiment is illustrated. The diaper 10 is of a substantiallyrectangular configuration; however, it is contemplated that any othersuitable configuration may be employed. In this embodiment, the middleportion is contoured in an “hourglass” configuration to fit comfortablyaround a wearer's thighs when the diaper 10 is secured to the wearer.

The diaper 10 generally consists of several layers, as shown in FIG. 2.FIG. 2 is a cross-sectional view of the diaper 10 generally alongsection line 2-2 shown in FIG. 1. The diaper 10 includes an inner layer12, an absorbent layer 14, and an outer layer 16. The inner layer 12faces a wearer and contacts the skin of the wearer when the diaper 10 issecured to the wearer. The inner layer 12 can be composed of anymoisture-pervious fabric suitable to allow bodily discharge to passthrough the inner layer 12 and be absorbed by the absorbent layer 14.Non-limiting examples of materials suitable to form the inner layer 12include polypropylene, polyethylene, polyester, materials havinghydrophobic properties, combinations thereof and/or the like.Additionally, the inner layer 20 can be treated with a hydrophilicfinish to improve pass through of liquids to diaper layers beneath theinner layer 20. Non-limiting examples of suitable hydrophilic finishesinclude anionic surfactants, cationic surfactants, nonionic surfactants,wetting agents (e.g., silicon based surfactants, glycol basedsurfactants), combinations thereof and/or the like. As will be discussedin greater detail below, the inner layer 12 is typically formed from aplastic resin of any of the above-referenced materials. This inner layer12 is substantially co-extensive with the outer layer 16.

The absorbent layer 14 is positioned between the inner layer 12 and theouter layer 16. The absorbent layer 14 may be composed of any materialssuitable for absorbing the fluids and discharge including, but notlimited to, a fibrous material (e.g., fluffed wood pulp), a superabsorbent polymer (SAP), or the combination of SAP and fibrous material.The SAP can be natural or synthetic and may be biodegradable.Non-limiting examples of SAP include polymers based on acrylate(s) suchas sodium acrylate, potassium acrylate, and/or an alkyl acrylate(s)(e.g., methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate,and hexyl acrylate). The absorbency of the diaper 10 may vary dependingupon whether it is intended for use by infants, children and/or adults.

The outer layer 16, which faces away from the wearer when the diaper 10is secured to the wearer, is composed of a moisture-impervious fabric.Accordingly, the outer layer 16 may be made of any material suitable tominimize or prevent fluids and other discharge from escaping the diaper.Non-limiting examples of suitable materials for the outer layer 16include polyethylene and/or breathable poly. According to someembodiments, the outer layer 12 can be a thin film such as, for example,polyethylene film. As will be discussed in greater detail below, theouter layer 16 is typically formed from a plastic resin of any of theabove-referenced materials. This outer layer 16 that prevents diapersfrom leaking also prevents air circulation, thus creating a warm, moistenvironment where bacteria and fungi can thrive. This bacteria and fungican cause infectious diseases, unpleasant odors, urinary tractinfections, bladder infections, kidney infections, diaper rashes and thelike.

The absorbent layer 14 is treated with at least one antimicrobial agentto prevent or substantially minimize the risk of these microbe-relatedeffects by either killing or inhibiting the growth of microbes such asbacteria, microbial pathogens, fungi, and viruses. Not all antimicrobialagents can kill or inhibit the growth of all microbes. Rather, any oneparticular antimicrobial agent generally has a range of microbe typesthat the antimicrobial agent is effective against. As such, a variety ofantimicrobial agents and/or combinations of antimicrobial agents may beapplied to the absorbent layer 14 to provide protection against a broadrange of microbes. Non-limiting examples of suitable antimicrobialagents for use in the embodiments described herein include cationicantimicrobial polymers (e.g., polyhexamethylene biguanide (PHMB)), mono-or poly-quaternary ammonium salt (QAS) based antimicrobials (e.g.,trialkoxysilyl quaternary ammonium salt,3-trimethoxy-silyl-propyldimethyloctadecyl ammonium chloride and itshydrolyzed product, polyquat-1), chlorinated phenoxy-basedantimicrobials (e.g., triclosan), pyrithione based antimicrobials (e.g.,zinc pyrithione), cationic polysaccharides (e.g., chitosan),aminopolysaccharides (e.g., chitin or chitosan derivatives),benzalkonium compounds (e.g., benzalkonium chloride, and a mixture ofbenzalkonium chloride, silver nitrate), nitro compounds (e.g.,5-nitrofurylacrolein), dimethylbenzylammonium chloride, chlorhexidines(e.g., chlorhexidine, chlorhexidine acetate, chlorhexidine gluconate,chlorhexidine hydrochloride), crosslinked polyethylene glycols andpolyethylene glycols of differing molecular weights, hydantoinderivatives with halamine bond, antibiotics (e.g., polymycine, neomycin,kanamycin, grisofulvien), natural extracts with antimicrobial properties(e.g., grape fruit seed, hops, tea oil, aloe, thyme, rosemary,peppermint, basil, ginger), metallic materials in the form of metals(e.g., silver, copper, zinc materials and their oxides and salts), metaloxides (e.g., zinc oxide, silver oxide), metal salts (e.g., silverchloride, silver nitrate), metal complexes (e.g., silver-zinc zeolite),organo-metallics (e.g., tributylin maleate), combinations thereof or thelike. Additional examples of suitable commercially availableantimicrobial agents are Haloshield® technology manufactured by MedlineInc., which is currently headquartered at One Medline Place, Mundelein,Ill. 60060 or HaloSource Inc., which is currently headquartered at 1631220^(th) Street SE, Bothell, Wash. 98021 and SilverClear® manufacturedby Transtex Technologies, which is currently headquartered at 9600Ignace St. Suite D, Brossard, Quebec, Canada J4Y2R4.

Generally, antimicrobial agents are classified as antibacterial agents(e.g., antibiotics, disinfectants, and antiseptics), antifungal agents,and antiviral agents depending upon the primary use of the particularagent. For example, if an antimicrobial agent is primarily used totarget fungi, the antimicrobial agent may be referred to as anantifungal agent. However, it is to be understood that theseclassifications are non-limiting. For example, an antibacterial agentmay be effective against fungi and an antifungal agent may be effectiveagainst bacteria. Therefore, it is to be understood that the absorbentlayer 14 can be treated with any combination of antibacterial agent(s),antifungal agent(s), and/or antiviral agent(s).

Unfortunately, treating the absorbent layer 14 with certainantimicrobial agents can cause skin irritation for wearers. Skinirritation is an especially significant problem for wearers withsensitive skin or for wearers having a diaper rash. Skin irritation isoften exacerbated by diaper-related substances such as colorant dyes.

To address the problems associated with skin irritation caused by thepresence of antimicrobial agents, the inventors attempted to treat theinner layer 12, which contacts the wearer's skin, with at least one skinconditioner/moisturizer. It was discovered that substances including aquantity of polydimethylsiloxane, also known as dimethicone, areparticularly effective at minimizing skin irritation. Dimethicone is aliquid silicone of high molecular weight in water emulsion, which actsas an emollient to soften and condition skin. Substances includingdimethicone provide a breathable moisture barrier to protect againstmoisture, help block transepidermal water loss, sooth chapped, crackedskin and help relieve itching. One nonlimiting example of a commerciallyavailable substance containing dimethicone is Medline Remedy®Dimethicone Barrier Cream, which is currently manufactured by MedlineInc., which is currently headquartered at One Medline Place, Mundelein,IL 60060. The chemical structure of dimethicone is(H₃C)₃SiO[Si(CH₃)₂O]_(n)Si(CH₃)₃, where n is the number of repeatingmonomer [SiO(CH₃)₂] units. According to some embodiments, it iscontemplated that the inner layer 12 can be treated with a substancehaving a concentration of about 5% dimethicone; however any othersuitable concentration may be utilized.

Surprisingly, it was also discovered that some skinconditioners/moisturizers enhance the antimicrobial effect of anantimicrobial agent through synergistic action when the skinconditioner/moisturizer mixes with the antimicrobial agent. Skinconditioners/moisturizers that interact synergistically withantimicrobial agents are hereinafter referred to as “preservativeboosters.” Non-limiting examples of commercially available preservativeboosters include Symdiol-68®, Symdiol-68T®, Symclariol® and Hydrolite®manufactured by Symrise Inc., which is currently headquartered at 300North Street, Teterboro, N.J. 07608. Symdiol 68® and Symdiol 68T® aregenerally classified as alkanediols and can be used alone or incombination in the present concepts. Specifically, Symdiol 68® includes1,2-hexanediol and 1,2-octanediol, Symdiol 68T® includes 1,2-hexanediol,1,2-octanediol and tropolone, Symclariol® includes 1,2-decanediol, andHydrolite® includes 1,2-pentanediol. Other non-limiting examples ofpreservative boosters include aloe, alkyl diols, combinations thereofand/or the like.

Preservative boosters are a subset of a broader category of chemicals orsubstances called antimicrobial boosters that can be applied to theinner layer 12 of the diaper 10 to address the problem of skinirritation caused by the presence of antimicrobial agents. As usedherein, an “antimicrobial booster” is any chemical or substance thatincreases the antimicrobial effect of an antimicrobial agent throughsynergistic action when mixed with the antimicrobial agent. Anon-limiting example of an antimicrobial booster isethylenediaminetetraacetic acid (EDTA). According to some embodiments,it is contemplated that the inner layer 12 can be treated with theantimicrobial booster(s) at a concentration level of about 0.5%;however, any other suitable concentration may be utilized such as, forexample, about 0.1% to about 5.0% concentration levels. The combinationof an antimicrobial agent(s) and an antimicrobial booster(s) inabsorbent articles is also disclosed in related patent application Ser.No. 12/233,215 filed on Sep. 18, 2008, which is hereby incorporated byreference in its entirety.

While the description that follows specifically relates to absorbentarticles having an inner layer 12 treated with an antimicrobial agent,it is contemplated that the inner layer 12 can be treated with anantimicrobial booster(s), a substance(s) including dimethicone or acombination thereof that is a combination of a substance(s) includingdimethicone and an antimicrobial booster(s). Many of the benefitsdescribed below with respect to an inner layer 12 treated with anantimicrobial booster(s) are also applicable to an inner layer 12treated with a substance(s) including dimethicone or a combination of asubstance(s) including dimethicone and an antimicrobial booster(s).

Prior to urination or defecation, the wearer is substantially insulatedfrom the antimicrobial agent(s) present in the absorbent layer 14because the absorbent layer 14 is disposed beneath the inner layer 12.As the inner layer 12 is the layer that contacts the wearer's skin, ifthe inner layer 12 is treated with an antimicrobial booster(s) that is apreservative booster(s), the conditioning and moisturizing effects ofthe preservative booster(s) help to maintain healthy skin and minimizeany irritation or dryness that would otherwise result fromdiaper-related substances (e.g., colorant dyes) or trace amounts ofantimicrobial agents that permeate from the absorbent layer 14 to theinner layer 12. Some antimicrobial boosters have inherent antimicrobialproperties that provide minor protection against bacteria and fungi;however, a diaper treated with just an antimicrobial booster(s) wouldnot have sufficient antimicrobial properties to adequately prevent orinhibit the growth of bacteria and/or fungi due to urine, feces, orother bodily discharge.

Urination, defecation, or release of other bodily discharges into thediaper 10 introduces moistures that permeate the inner layer 12 andabsorb into the absorbent layer 14. The moistures mix with theantimicrobial booster(s) present in or on the inner layer 12 causing theantimicrobial booster(s) to also absorb into the absorbent layer 14 andsynergistically combine with the antimicrobial agent(s). The synergisticaction between the antimicrobial booster(s) and antimicrobial agent(s)enhances the antimicrobial effectiveness of the antimicrobial agent.Consequently, the combination of the antimicrobial booster(s) and theantimicrobial agent(s) acts faster and requires smaller concentrationsor quantities to achieve a particular microbe kill rate than either theantimicrobial booster(s) or the antimicrobial agent(s) wouldindividually.

There are several additional benefits to combining the antimicrobialbooster(s) and antimicrobial agent(s) as described above. Because asmaller quantity of the antimicrobial agent(s) is needed to treat theabsorbent layer 14, skin irritation due to the antimicrobial agent(s) isminimized. Skin irritation caused by antimicrobial agent(s) or otherdiaper related substances (e.g., colorant dyes) is further reduced bythe skin conditioning and moisturizing properties of an antimicrobialbooster(s) that is a preservative booster(s).

Reducing skin irritation not only increases the diaper wearer's comfort,it further permits a broader spectrum of antimicrobial agents to beutilized. Generally, diapers having an antimicrobial agent(s) butlacking an antimicrobial booster(s) are limited in the antimicrobialagents that can be used because some antimicrobial agents impermissiblyirritate the wearer's skin. Because not all antimicrobial agents areeffective against all microbes, a diaper limited to only inherentlynon-irritating antimicrobial agents may not be as effective against atargeted group of microbes as other antimicrobial agents. This problemmay be exacerbated in the future because microbes continually developresistances to commonly-used antimicrobial agents. A diaper includingthe synergistic combination of the antimicrobial booster(s) andantimicrobial agent(s) described herein can minimize the irritatingeffects of some antimicrobial agents previously considered unsuitable toa level that is permissible and, thus, broaden the spectrum ofantimicrobial agents available. For example, the antimicrobial agentchlorhexidine is widely known to cause mild to moderate irritation whenapplied to the skin. For this reason, chlorhexidine is generally notconsidered for use as an antimicrobial agent in diapers. Yet,surprisingly when chlorhexidine is combined with an antimicrobialbooster, a smaller quantity or concentration of chlorhexidine isrequired and, thus, skin irritation from the presence of chlorhexidinecan be minimized or reduced to an acceptable level such that thismaterial can be used in diapers.

Incidentally, because the antimicrobial agent(s) can have a negativeimpact on the environment, reducing the quantity or concentration of theantimicrobial agent(s) in the diaper by using an antimicrobial boosteralso lessens the environmental impact of diapers discarded in landfills.

Referring to FIG. 3, the operational flow of a method for manufacturinga disposable diaper 100 according to one of the embodiments describedabove is illustrated.

As disclosed above, the absorbent layer 14 can be formed from acombination of SAP and a fibrous material such as wood pulp. At block110, the fibrous material is treated with at least one antimicrobialagent(s) by any process suitable to either absorb the antimicrobialagent(s) within or onto the fibers of the fibrous material (i.e.,leaching) or covalently bond the antimicrobial agent(s) to the fibrousmaterial (i.e., non-leaching). Depending upon the antimicrobial agent(s)selected, a binder may be required to facilitate bonding theantimicrobial agent(s) to the fibrous material and/or absorbing theantimicrobial agent(s) within or onto the fibrous material. Non-limitingexamples of suitable binders include acetate, acrylate, acrylamide,urethane, vinyl, ester, other monomers, combinations thereof or thelike. For example, the fibrous material can be dipped into or sprayedwith a quantity of the antimicrobial agent(s).

At block 112, the absorbent layer 14 is formed from the SAP and thefibrous material by any suitable process. For example, the absorbentlayer 14 can be formed on a conveyor belt passing under a series ofpressurized nozzles. Depending upon the desired densities anddistributions of SAP and fibrous material within the absorbent layer 14,a particular pressurized nozzle in the series of pressurized nozzles mayspray SAP particles, fibrous material, or a mixture of SAP and fibrousmaterial onto the conveyor surface. The bottom of the conveyor beltsurface is perforated and a vacuum is applied from below so that thefibers are pulled down to form a long flat absorbent layer 14 as thematerials are sprayed onto the conveyor belt. An absorbent layer 14 ofuniform thickness can be achieved by a leveling roller used to remove atop portion of the SAP and/or fibrous material. According to alternativeembodiments, it is contemplated that the absorbent layer 14 is composedof only the fibrous material by any suitable process such as the processdescribed above.

At blocks 114 and 116, the inner layer 12 and the outer layer 16 arerespectively formed by any dry laid or wet laid process. For example,the inner layer 12 and the outer layer 16 may be formed by a melt blownprocess, spunbond process, spunlace process, spunlaid process or thelike. According to a melt blown process, a plastic resin (e.g.,polypropylene or polyethylene) is melted and extruded though small holesby air pressure. The fibers condense onto a sheet as the air-blownstream of fibers cools. Heated rollers are then used to flatten thefibers and bond them together. The result is a “web” of nonwoven fabric,which can be rolled to form a bolt of fabric.

At block 118, the inner layer 12 is treated with at least oneantimicrobial booster, at least one substance including dimethicone or acombination thereof. The antimicrobial booster(s) and/or thesubstance(s) including dimethicone can be applied to the inner layer 12by any suitable process such as, for example, spraying, foaming (i.e.,applying a foam containing the antimicrobial booster(s) and/or asubstance including dimethicone to the inner layer 12), dipping,combinations thereof, or the like. According to an alternativeembodiment, the antimicrobial booster(s) and/or substance(s) includingdimethicone can be mixed with the plastic resin prior to forming theinner layer 12 at block 114.

At this point in the manufacturing process, an inner layer 12, anabsorbent layer 14, and an outer layer 16 have been formed. At block120, the absorbent layer 14 is interposed between the inner layer 12 andthe outer layer 16 by, for example, feeding the absorbent layer 14 ontoa conveyor with the outer layer 16 and then feeding the inner layer 12into place above the absorbent layer 14. At block 122, the interposedlayers are joined by a suitable means such as, for example, gluing,heating, ultrasonic welding, calendaring, combinations thereof or thelike. The assembled layers are cut to a shape and size required for theparticular absorbent article being manufactured.

It is contemplated that various additional features can be added to thediapers 10 at any point in the process described above. For example, oneor more fasteners can be integrally formed with or attached to the innerlayer 12, the outer layer 16, or both to secure the diaper 10 to thewearer. Referring back to FIG. 1, two fasteners 18 attached to the outerlayer 16 are illustrated. It is contemplated that any suitable type offasteners may be used such as, for example, adhesives, hook and loopmechanical fasteners, hook fasteners for attachment to the outer layerof the diaper, combinations thereof or the like. Additionally, elasticbands may be added to facilitate a snug fit or prevent leakage.

It will be appreciated by those skilled in the art that many of thesteps for manufacturing the diaper 10 can be performed in a differentorder than that described above. For example, the absorbent layer 14,the inner layer 12, and the outer layer 16 can be formed in any order.Additionally, the inner layer 12, the absorbent layer 14, and the outerlayer 16 can be cut into the shape of the absorbent article prior tointerposing the layers or joining the layers. Although directly treatingthe SAP with the antimicrobial agent(s) causes the SAP to lose some ofits absorption capacity, it is also contemplated that according to someembodiments, the absorbent layer 14 may be formed from the fibrousmaterial and SAP first and then treated with the antimicrobial agent(s).Alternatively, a mixture of SAP and fibrous material can be treated withthe antimicrobial agent(s) and then formed into the absorbent layer 14.

While the present invention has been described with reference to one ormore particular embodiments, those skilled in the art will recognizethat many changes may be made thereto without departing from the spiritand scope of the present invention. Each of these embodiments andobvious variations thereof is contemplated as falling within the spiritand scope of the invention, which is set forth in the following claims.

What is claimed is:
 1. A method of manufacturing an absorbent articlecomprising: forming a moisture-impervious outer layer; forming an innerlayer; treating the inner layer with at least one substance includingpolydimethylsiloxane; treating a quantity of fibrous material with atleast one antimicrobial agent; forming an absorbent layer from thefibrous material; interposing the absorbent layer between the outerlayer and the inner layer; and joining the inner layer, the absorbentlayer, and the outer layer to form the absorbent article.
 2. The methodof claim 1, wherein the treating the inner layer comprises spraying theinner layer with the at least one substance includingpolydimethylsiloxane.
 3. The method of claim 1, wherein the inner layeris formed from at least one plastic resin and the treating the innerlayer comprises mixing the at least one plastic resin with the at leastone substance including polydimethylsiloxane prior to forming the innerlayer.
 4. The method of claim 1 further comprising adding one or moresuper absorbent polymers to the fibrous material prior to forming theabsorbent layer.
 5. The method of claim 4, wherein the one or more superabsorbent polymers are added to the fibrous material after treating thefibrous material with the antimicrobial agent.
 6. The method of claim 1further comprising cutting the joined inner layer, absorbent layer, andouter layer to the shape of a diaper.
 7. The method of claim 1 furthercomprising cutting the joined inner layer, absorbent layer, and outerlayer to the shape of an underpad.
 8. The method of claim 1, wherein theat least one antimicrobial agent is polyhexamethylene biguanide.
 9. Themethod of claim 1, wherein the at least one antimicrobial agentcomprises at least one of cationic antimicrobial polymers,mono-quaternary ammonium salt based antimicrobials, poly-quaternaryammonium salt based antimicrobials, chlorinated phenoxy-basedantimicrobials, pyrithione based antimicrobials, cationicpolysaccharides, aminopolysaccharides, benzalkonium compounds, nitrocompounds, dimethylbenzylammonium chloride, chlorhexidines, crosslinkedpolyethylene glycols of differing molecular weights, polyethyleneglycols of differing molecular weights, hydantoin derivatives withhalamine bond, antibiotics, natural extracts with antimicrobialproperties, metallic materials, and combinations thereof.
 10. The methodof claim 1, wherein the at least one antimicrobial agent comprises atleast one of polyhexamethylene biguanide, trialkoxysilyl quaternaryammonium salt, 3-trimethoxy-silyl-propyldimethyloctadecyl ammoniumchloride, polyquat-1, triclosan, zinc pyrithione, chitosan, chitosanderivatives, chitin derivatives, benzalkonium chloride, a mixture ofbenzalkonium chloride and silver nitrate, 5-nitrofurylacrolein,chlorhexidine, chlorhexidine acetate, chlorhexidine gluconate,chlorhexidine hydrochloride, polymycine, neomycin, kanamycin,grisofulvien, grape fruit seed, hops, tea oil, aloe, thyme, rosemary,peppermint, basil, ginger, silver, copper, zinc, zinc oxide, silveroxide, silver chloride, silver nitrate, silver-zinc zeolite, tributylinmaleate, and combinations thereof.
 11. The method of claim 1, whereinthe inner layer is further treated with at least one antimicrobialbooster.
 12. The method of claim 11, wherein the at least oneantimicrobial booster comprises two or more 1,2-alkanediols.
 13. Themethod of claim 11, wherein the at least one antimicrobial boostercomprises 1,2-hexanediol, 1,2-octanediol, and tropolone.
 14. The methodof claim 11, wherein the at least one antimicrobial booster comprisesone or more alkyl diol.